Catalyst for simultaneous hydrotreating and hydrodewaxing of hydrocarbons

ABSTRACT

Waxy shale oil feeds containing organonitrogen and/or organosulfur components are contacted with a catalyst comprising a Group VIB metal component on a support containing silicalite and a porous refractory oxide under conditions of elevated temperature and pressure and in the presence of hydrogen so as to simultaneously reduce its pour point and its organosulfur and/or organonitrogen content.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Pat. Application Ser.No. 172,868 filed July 28, 1980 and now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to the catalytic treatment of hydrocarbons in thepresence of hydrogen and under conditions of elevated temperature andpressure. More particularly, it relates to treating waxy paraffinichydrocarbons, particularly full boiling range shale oils, so as tosimultaneously lower the pour point thereof by catalytic hydrodewaxingand lower the organosulfur and/or organonitrogen contents thereof bycatalytic hydrotreating.

Many hydrocarbon liquid feedstocks have the undesirable properties ofhigh pour point, which causes pumping difficulties under low temperatureconditions, and high organonitrogen and/or organosulfur contents, whichare undesirable from the standpoint that such components deactivatecertain refining catalysts or, if present in the ultimate product whencombusted, contribute to atmospheric pollution. One such feedstock israw shale oil, a feedstock obtained by retorting oil shale, such as theoil shale found in the Colorado River formation in the western UnitedStates. When retorted under temperature conditions above about 900° F.,a material in the oil shale known as kerogen decomposes, releasing shaleoil vapors, which are condensed and collected by known techniques toproduce raw liquid shale oil. Such raw shale oil is undesirable becauseit usually contains solid particulates, arsenic, and organonitrogenand/or organosulfur components. In addition, the raw shale oil has ahigh pour point, usually in the range of 50° to 90° F., indicative ofthe presence of a relatively high proportion of wax components, i.e.,straight chain and slightly branched paraffins of high molecular weight.

Raw shale oil may be treated by known techniques to reduce the ash andarsenic contents thereof, and it is now known by the teachings in U.S.Pat. No. 4,153,540 issued to Gorring et al. that shale oil can beupgraded by a two-step method in which the shale oil is first contactedwith a hydrotreating catalyst under conditions such that theorganosulfur and organonitrogen contents of the shale oil are reduced.Subsequently, the hydrotreated shale oil is contacted with ahydrodewaxing catalyst under conditions (750° to 1000° F., 500 to 1500psig, 0.25 to 1.0 LHSV, and a hydrogen feed rate of 5 to 6 moles permole of feedstock) such that the feedstock is hydrodewaxed while its750° F.+ fraction is converted by at least 50% to products boiling below750° F. The hydrodewaxing catalyst employed by Gorring et al. is similarto that of Chen et al. described in U.S. Pat. No. Re. 28,398, that is,it comprises a ZSM-5 zeolite in its hydrogen form combined with a metalhaving activity for promoting hydrogenation/dehydrogenation reactions.

Although the two-step process described in U.S. Pat. No. 4,153,540results in a significant reduction in the pour point of the shale oil,it also results in a shale oil product that contains undesirableproportions of organosulfur and organonitrogen components. Inparticular, the shale oil products reported in the Examples of U.S. Pat.No. 4,153,540 contain excessively high proportions of total nitrogen.One product, for example, contained 1.10 wt. % total nitrogen,representing only about a 50% reduction in organonitrogen componentsafter two hydroprocessing steps. By most refining standards, such ashale oil product would require yet more hydrotreating to reduce thenitrogen content still further, for example, to below about 250 wppm.

In addition, the hydrodewaxing catalyst described in U.S. Pat. No.4,153,540 exhibits an undesirable amount of hydrocracking. Ideally, onewould want to treat the shale oil so as to substantially reduce itsorganosulfur and organonitrogen contents and its pour point without also(as would be the case in severe hydrocracking) substantially alteringthe boiling characteristics of the shale oil. But in the processdescribed in U.S. Pat. No. 4,153,540, it appears that the hydrocrackingis indiscriminate, that is, the waxy paraffins are hydrocrackedsufficiently to lower the pour point but not without also cracking 50%or more of the 750° F.+ components as well. Such excessive hydrocrackingis especially undesirable if the shale oil is treated for pour pointreduction at a distance remote from an oil refinery; it forces one toemploy extensive recovery facilities for handling light end materialssuch as propane and butane and for generating hydrogen in a locationwhere such is usually impractical. Additionally, and perhaps moreimportantly, to hydrocrack a shale oil so as to convert 50% or more ofthe 750° F.+ fraction while only about 50% of the nitrogen is removed isan inefficient use of hydrogen, particularly when severe hydrocrackingis not desired but low nitrogen-containing shale oil products are.

Accordingly, it is one of the objects of the present invention toprovide a process for substantially reducing the pour point, sulfurcontent, and nitrogen content of shale oil feedstocks and other waxyhydrocarbon feedstocks while minimizing the amount of hydrogen consumed.It is another object to provide such a process having the furtheradvantage of selectively hydrocracking the waxy paraffins while notsubstantially hydrocracking other components. It is yet another objectto provide a process wherein a shale oil feedstock containing more thanabout 0.2 wt. % organosulfur components, and more than about 1.50 wt. %organonitrogen components, and having a pour point above about 50° F. isconverted, without substantially disturbing the boiling characteristicsof the shale oil, to a shale oil product having a pour point below about30° F. and containing less than about 400 wppm organo-nitrogen compoundsand less than 25 wppm organnosulfur compounds. It is yet another objectto provide a catalyst having high activity for selectively hydrocrackinga waxy, sulfur-containing and nitrogen-containing hydrocarbon feedstocksuch that a substantial reduction in the wax content thereof, asevidenced by a substantial reduction in pour point, is obtainedsimultaneously with a substantial reduction in the organosulfur andorganonitrogen compounds contents. These and other advantages willbecome more apparent in view of the following description of theinvention.

SUMMARY OF THE INVENTION

It has now been discovered that a catalyst comprising a Group VIB metalcomponent on a support comprising an intimate admixture of a porousrefractory oxide and a silica polymorph consisting essentially ofcrystalline silica is useful in hydrocarbon dewaxing processes, andparticularly for the simultaneous dewaxing and denitrogenation ofhydrocarbons.

It has also been discovered in the present invention that waxyhydrocarbon feedstocks having relatively high pour points and containingorganosulfur and/or organonitrogen compounds may be simultaneouslyhydrodewaxed and hydrotreated by contact under conditions of elevatedtemperature and pressure and the presence of hydrogen with ahydroprocessing catalyst comprising a Group VIB metal component on asupport comprising an intimate admixture of a porous refractory oxideand silicalite or other crystalline silica molecular sieve essentiallyfree of aluminum and other Group IIIA metals but having channels withapertures defined by ten membered rings of oxygen atoms. In comparisonto the feedstock, the product hydrocarbon is substantially reduced inpour point, organonitrogen components, and organosulfur components.

It has also been discovered that the catalyst of the invention is mostespecially useful for simultaneously hydrotreating and hydrodewaxing awaxy, full boiling range shale oil that has previously been deashed,dearsenated, and hydrotreated but still contains unacceptableproportions of organosulfur and/or organonitrogen components and has anunacceptably high pour point. One of the advantages of the catalyst ofthe invention is that, even under relatively severe hydroprocessingconditions as, for example, 2000 psig and 750° F., the waxy componentsand organosulfur and organonitrogen components are removed withoutsubstantially altering the boiling characteristics of the feedstockbeing treated, particularly with respect to the heavy fractions thereof.

For purposes herein, the crystalline silica molecular sieves used as acomponent of the catalyst of the invention are considered essentiallyfree of Group IIIA metals when they contain less than about 0.75 weightpercent of such metals, calculated as the trioxides thereof, e.g., Al₂O₃. All silicalites considered herein are essentially free of Group IIIAmetals. Also, all reference herein to proportions of organosulfur ororganonitrogen components, calculated as sulfur or nitrogen,respectively, refers to the weight proportion of total sulfur ornitrogen in the liquid hydrocarbon under consideration. Thus, forexample, a liquid hydrocarbon weighing 100 grams and containing 40 gramsof organonitrogen components, only 1 gram of which is due to nitrogenatoms, contains 1 weight percent of organonitrogen components calculatedas nitrogen. There are standard tests known in the petroleum industryfor determining the proportions of total nitrogen and total sulfur in aliquid hydrocarbon, such as the Kjeldahl test for nitrogen.

DETAILED DESCRIPTION OF THE INVENTION

The process of the present invention is directed to lowering the pourpoint of waxy hydrocarbon feedstocks by contact with a catalyst underconditions of elevated temperature and pressure in the presence ofhydrogen. Contemplated feedstocks include waxy raffinates or waxydistillates boiling above about 650° F. Such feedstocks, which oftenhave pour points above 70° F., usually above 80° F., and more usuallystill, above 90° F., may be treated in the process of the invention toproduce a lubricating oil of low pour point, i.e., below +30° F.Organonitrogen and organosulfur compounds, which may also be present inthe waxy raffinate to be dewaxed, are substantially reduced in theprocess of the invention, usually from above about 400 wppm to less than50 wppm in the case of organosulfur components and from above about 125wppm to less than about 100 wppm, usually less than 75 wppm, in the caseof organo-nitrogen components.

Other typical feedstocks for treatment herein have a pour point above50° F., an organonitrogen content (calculated as nitrogen) above about200 wppm, often above 500 wppm, and an organosulfur content (calculatedas sulfur) above about 25 wppm. The preferred feedstock is a full rangeshale oil or a fraction thereof, and the most preferred feedstock is afull range shale oil that has been successively deashed, as byfiltration or electrostatic agglomeration, dearsenated, as by theprocess described in U.S. Pat. No. 4,046,674, herein incorporated byreference in its entirety, and catalytically hydrotreated, as by contactwith a hydrotreating catalyst comprising Group VIB and Group VIII metalcomponents on a porous refractory oxide support. When such a sequentialdeashing-dearsenating-hydrotreating method is applied to shale oilsderived by retorting oil shale found in the Colorado River formation andadjacent areas, the full boiling range shale oil will typically have aboiling point range between about 80° F. and about 1030° F., anorganonitrogen content between about 200 and 3500 wppm, usually betweenabout 300 and 2000 wppm, an organosulfur content between about 30 and2000 wppm, usually between about 35 and 100 wppm, and a pour point aboveabout 70° F., usually between about 75° and 90° F.

For a typical raw shale oil derived from retorting Colorado oil shale,the sequential treatment specified in the preceding paragraph willgenerally alter the chemical and pour point characteristics of the oilas shown in Table I, with it being specifically noted that thedearsenating step, wherein a sulfided nickel and molybdenum-containingcatalyst, usually containing between about 30 and 70 wt. % nickelcomponents, calculated as NiO, and between 2 and 20 wt. % molybdenumcomponents, calculated as MoO₃, on a porous refractory oxide support,such as alumina, is effective for lowering the sulfur and nitrogencontents as well as the arsenic content of the deashed shale oil.

                  TABLE I                                                         ______________________________________                                                   Typical         Dear-    Hydro-                                               Raw    Deashed  senated  treated                                              Shale  Shale    Shale    Shale                                                Oil    Oil      Oil      Oil                                       ______________________________________                                        Pour Point, °F.                                                                     50-65    50-65    50-70  65-90                                   Sulfur, wt. % as S                                                                         0.5-1.5  0.5-1.5  0.2-1.0                                                                              0.003-0.2                               Nitrogen, wt. % as N                                                                       1.6-2.2  1.6-2.2  1.4-2.0                                                                              0.020-0.350                             Arsenic, wppm as As                                                                        40-70    20-30    <1     <1                                      ______________________________________                                    

In accordance with the invention, the shale oil or other waxyhydrocarbon feedstock is contacted with a particulate catalyst describedmore fully hereinafter. Usually the contacting will be accomplished in asuitable reactor vessel under conditions of elevated temperature andpressure, with pressures above about 750 psig, usually above 1000 psigbeing suitable, and between about 1500 and 3000 psig being preferred,and with temperatures above about 650° F. being suitable andtemperatures between about 650° and 800° F. being most suitable,primarily because temperatures above about 800° F. usually exceed themetallurgical temperature constraints of commercial, high pressure steelreactors. The rate at which the feedstock is passed through the reactorin contact with the catalyst particles is usually at a liquid hourlyspace velocity between about 0.1 and 10.0, but preferably between about0.5 and 2.0. Hydrogen is also required and is usually passed through thereactor at a rate above about 500 standard cubic feet per barrel offeedstock, preferably between about 1500 and 15,000 standard cubic feetper barrel.

Under conditions selected from the foregoing, and with the catalyst tobe described hereafter, substantial reductions in pour point,organonitrogen content, and organosulfur content are obtainable. It hasbeen found, as will be demonstrated in Example II hereinafter, that awaxy deashed-dearsenated shale oil feedstock having a pour point of 55°F., an organonitrogen content of 1.8 wt. %, and an organosulfur contentof 0.835 wt. % can be converted to a product composition having a pourpoint of -10° F., an organonitrogen content of 118 wppm, and anorganosulfur content of 23 wppm under conditions of 1.0 liquid hourlyspace velocity, an operating pressure of 2000 psig, a hydrogen feed rateof 10,000 standard cubic feet per barrel, and an operating temperatureof about 800° F. In general, in the presence of the catalyst of theinvention, reductions in organonitrogen contents over 75% complete andorganosulfur contents over 50% complete are obtainable, whilesubstantial reductions in the pour point are simultaneously achieved.

Catalysts useful in the present invention are composed of one or moreGroup VIB active metal components, particularly the Group VIB metals,oxides, and sulfides, on a support comprising an intimate admixture of aporous refractory oxide and an essentially Group IIIA metal-freecrystalline silica molecular sieve having channels with aperturesdefined by eight or ten member rings of oxygen atoms. The preferredcatalyst contains, in addition to Group VIB metal components, one ormore Group VIII metal components, particularly the metals, oxides, andsulfides of the iron Group VIII elements, i.e., iron, cobalt, andnickel. Especially contemplated are catalysts containing a nickel and/orcobalt component in combination with a tungsten and/or molybdenumcomponent. The most highly preferred catalyst comprises both nickel andtungsten components, especially in the sulfide form. The proportion byweight of the catalyst that comprises the Group VIB metal components isbetween about 5 and 40%, preferably between about 15 and 30%, calculatedas the metal trioxide. The proportion by weight of the catalyst thatcomprises the Group VIII metal components is between about 0.5 and 15%,preferably between about 1 and 5%, calculated as the metal monoxide.

The porous refractory oxides useful as supports in thehydrotreating-hydrodewaxing catalyst herein include the oxides ofdifficultly reducible metals, particularly those containing aluminum.Representative of such refractory oxides are alumina, silica, beryllia,chromia, zirconia, titania, magnesia, and thoria. Also representativeare silica-alumina, silica-titania, silica-zirconia,silica-zirconia-titania, zirconia-titania, and other such combinations.A specific refractory oxide known to be useful consists essentially of adispersion of finely divided silica-alumina in a matrix of alumina; thismaterial is more fully described in U.S. Pat. No. 4,097,365, hereinincorporated by reference in its entirety. The preferred refractoryoxide, however, is alumina, most preferably, gamma alumina, and as withall the refractory oxides contemplated herein, the preferred gammaalumina has a surface area above about 100 m² /gm.

Also included in the support, usually as a dispersion in the porousrefractory oxide, is a crystalline silica molecular sieve essentiallyfree of Group IIIA metals, in particular aluminum, gallium, and boron,with the most preferred silica molecular sieve for use herein being amaterial known as silicalite, a silica polymorph that may be prepared bymethods described in U.S. Pat. No. 4,061,724, issued to Grose et al.,herein incorporated by reference in its entirety. Silicalite may becharacterized as a crystalline molecular sieve comprising a channelsystem (or pore structure) of intersecting elliptical straight channelsand nearly circular straight channels, with openings in both types ofchannels being defined by 10 membered rings of oxygen atoms, suchopenings being between about 5 and 6 Angstroms in maximumcross-sectional dimension. As reported by Flanigen et al. in"Silicalite, a New Hydrophobic Crystalline Silica Molecular Sieve" inNature, Volume 271, pp. 512 to 516 (Feb. 9, 1978), silicalite is ahydrophobic crystalline silica molecular sieve having the property underambient conditions of adsorbing benzene (kinetic diameter 5.85 Å ) whilerejecting molecules larger than 6 Å, such as neopentane (kineticdiameter 6.2 Å). The silicalite disclosed in U.S. Pat. No. 4,061,724 isknown to have an X-ray powder diffraction pattern similar to ZSM-5, butrecently new silicas having X-ray powder diffraction patterns similar toZSM-11 have been discovered. (See Bibby et al., "Silicalite-2, a SilicaAnalog of the Aluminosilicate Zeolite ZSM-11" in Nature, Volume 280, pp.664 to 665 (Aug. 23, 1979).) While ZSM-11 type silicalites arecontemplated for use herein, the preferred silicalite is that having anX-ray powder diffraction pattern similar to ZSM-5, which silicalite isknown to have a mean refractive index of 1.39±0.01 when calcined in airfor one hour at 600° C. This same silicalite is also reported in U.S.Pat. No. 4,061,724 to have a specific gravity at 25° C. of 1.70±0.05g./cc., although Flanigen et al., in the Feb. 9, 1978, Nature articlepreviously specified, report the specific gravity as 1.76 g./cc. Itappears, therefore, that this silicalite has a specific gravity betweenabout 1.65 and about 1.80 g./cc., depending perhaps upon the method ofpreparation.

It should be emphasized that, although silicalite is similar to "ZSM-5family" members in having a similar X-ray powder diffraction pattern, itis dissimilar in two important aspects. Unlike the "ZSM-5 family,"silicalite is not an aluminosilicate, containing only trace proportionsof alumina, due to the commercial impossibility of removing contaminantaluminum components from the reagents used to prepare silicalite.Silicalite may contain up to about 0.75 wt. % alumina, calculated as Al₂O₃, and is usually prepared to contain more than about 0.15 wt. %alumina. Most silicalites contain less than about 0.6 wt. % alumina,calculated as Al₂ O₃. Additionally, as disclosed by Grose et al. in U.S.Pat. No. 4,061,724, neither "silicalite nor its silicate precursorexhibits ion exchange properties." Thus, silicalite does not share thezeolitic property of substantial ion exchange common to the crystallinealuminosilicates, and it therefore contains essentially no zeoliticmetal cations. It is, however, possible to prepare silicalite withmetals present therein as impurities but not as zeolitic cations (as byocclusion). Although operative for purposes herein, suchmetals-containing silicalites are not preferred. Silicalites containingtotal metals in only trace proportions, less than about 0.75 percent byweight, calculated as the metals, are preferred.

It should also be noted that silicalite, as taught by Grose et al., maybe prepared from a reaction mixture containing organic reagents. Organiccomponents may be present in the silicalite utilized in the invention,but such organic components are removed, usually to a proportion lessthan about 0.05 weight percent carbon, when the organic-containingsilicalite is calcined, as for example, by calcining for one hour in airat 600° C. in accordance with Grose et al.'s teachings. Thus, thecatalyst of the invention is preferably prepared with an essentiallyorganic-free, previously calcined silicalite. In an alternative butnonpreferred embodiment, the organic-containing silicalite is notcalcined until after it is admixed with the other components utilized toprepare the catalyst, e.g., the Group VIB component and gamma alumina.In other words, the silicalite becomes calcined during the same step ofthe catalyst preparation procedure designed primarily to convert themetal components to oxides. If this latter embodiment of the inventionis chosen, it is preferred that the calcining be such that essentiallyno organic materials remain in the catalyst. Calcining at 600° C. in airfor one hour in accordance with Grose et al.'s teachings is mostpreferred.

In the preferred embodiment of the invention the support consistsessentially of an intimate admixture of silicalite and a porousrefractory oxide such as alumina. The proportion of silicalite in thesupport may vary in the range of 2 to 90% by weight, but preferably thesupport consists essentially of a heterogeneous dispersion of silicalitein a matrix of alumina or other porous refractory oxide. Such adispersion contains silicalite in a minor proportion, usually betweenabout 15 and 45%, and more usually between 20 and 40% by weight, with30% being most highly preferred.

The catalyst of the invention is most preferably prepared in particulateform, with the clover-leaf particulate form shown in FIGS. 8 and 8A ofU.S. Pat. No. 4,028,227 being most highly preferred. One convenientmethod for preparing the catalyst involves first comulling a wettedmixture of calcined silicalite, an alumina gel, and an alumina bindermaterial, such as Catapal.sup.® peptized alumina, in proportionsappropriate to what is desired in the final catalyst support. Such acomulled mixture is then extruded through a die having suitable smallopenings therein in the shape of circles or ellipses, or as ispreferred, in the shape of three-leaf clovers. The extruded material iscut into small particulates, dried, and calcined, following which theresulting support particles are impregnated with a liquid solutioncontaining the desired Group VIB element in dissolved form, with otheractive components, such as nickel, or even an acidic component, such asphosphorus, known for its property to promote hydro-treating reactions,being optionally included. A specifically contemplated impregnationliquid consists essentially of an aqueous solution of dissolved ammoniummetatungstate and nickel nitrate, with the dissolved components beingpresent in the impregnation liquid in proportions sufficient to insurethat the final catalyst contains more than about 15% by weight tungstencomponents calculated as WO₃ and more than about 0.5% by weight nickelcomponents calculated as NiO. If desired, phosphorus components may alsobe present in the impregnation liquid so that the final catalystcontains, for example, more than about 0.5% by weight phosphoruscomponents calculated as P. After impregnation, the impregnatedcomposite particles are calcined in air at temperatures at or aboveabout 900° F. for a time period sufficient to convert the metalcomponents to oxide forms.

In an alternative method, the foregoing procedure is altered such that,instead of introducing the Group VIB and/or Group VIII metal componentsinto the support by impregnation, they are incorporated into thecatalyst by admixing an appropriate solid or liquid containing thedesired metal with the materials to be extruded through the die. Such amethod may prove less expensive and more convenient on a commercialscale than the impregnation method.

It is most highly preferred in the invention that the catalyst beconverted to the sulfide form, that is, to a form wherein the metalcomponents are converted in substantial part to sulfides. This may beaccomplished by contacting the catalyst with a gas stream consisting ofhydrogen and 10 volume percent hydrogen sulfide at an elevatedtemperature. Alternatively, if the waxy feedstock with which it is to becontacted contains organosulfur components, the catalyst may be merelyplaced into service in the oxide form, and under the conditionshereinbefore specified for simultaneously hydrowaxing and hydrotreatingsuch feedstocks, the catalyst is readily converted to the sulfide formin situ.

The foregoing catalyst has been found to have excellent catalyticproperties for promoting hydrotreating reactions and for selectivelyhydrocracking a waxy hydrocarbon so as to simultaneously lower itssulfur and/or nitrogen content and lower its pour point and viscositywithout otherwise substantially altering its chemical and physicalproperties. Especially noteworthy is the fact that the waxy feedstockmay be simultaneously hydrotreated and hydrodewaxed without an unduechange in the boiling point characteristics of the hydrocarbon beingtreated. There must, of course, be some change in boilingcharacteristics because hydrodewaxing is a form of hydrocracking, andhydrocracking of necessity produces hydrocarbons of lowered boilingpoints. But the catalyst of the invention is highly selective forhydrocracking waxy paraffins, and such is evidenced in the invention bythe sharp drop in pour point and the relatively small amount ofconversion of high boiling feed components into lower boiling products.Usually, no more than about 15 to 25% by volume of the high boilingcomponents, and particularly the components boiling above about 670° F.,are converted to lower boiling products. Such small percentageconversions of high boiling components are indicative of efficienthydrogen utilization, for the less hydrogen consumed in unnecessarilyhydrocracking non-waxy components or unnecessarily converting componentsother than the organosulfur and/or organonitrogen components, the lesscostly will be the hydrogenating facilities required to carry out theprocess of the invention.

Another advantageous feature of the catalyst of the invention is itsstability, that is, its long life for the intended simultaneoushydrodewaxing and hydrotreating reactions required to convert waxy shaleoils and the like into more valuable products. Virtually no deactivationof the preferred catalyst of the invention has been detected whenutilized under preferred conditions for time periods of more than onemonth.

The following two Examples are provided to illustrate the process of theinvention and to provide evidence of the superior properties of thecatalyst of the invention. No Example herein is provided to limit thescope of the invention; the invention is defined by the claims.

EXAMPLE I

A raw shale oil was deashed and catalytically dearsenated (as by amethod shown in U.S. Pat. No. 4,046,674), and the resulting treatedshale oil, containing more than about 1.5 wt. % organonitrogencomponents and more than about 0.5 wt. % organosulfur components, wascatalytically hydrotreated, the resulting feedstock having theproperties shown in Table II. The feedstock was passed through a reactorcontaining 130 ml (about 120 gm) of catalyst particles hereinafterdescribed at a liquid hourly space velocity of 1.0 v/v/hr, a pressure of2000 psig, and a temperature of about 737° F. To simulate the gas phasethat would be present if the feedstock were present with the gasesnormally recovered therewith from the catalytic hydrotreater, hydrogenwas fed into the reactor at a rate of about 8000 standard cubic feet perbarrel of feedstock fed into the reactor, thiophene was fed at a ratesufficient to simulate the amount of H₂ S produced from hydrotreating afeedstock containing 0.84 wt. % sulfur, and tertiary butylamine was fedat a rate sufficient to simulate the amount of ammonia that would beproduced from hydrotreating a feedstock containing 1.8 wt. %organonitrogen components.

The catalyst utilized in the reactor was prepared as follows: A mixtureof 30 wt. % silicalite, 50 wt. % gamma alumina powder, and 20 wt. %peptized Catapal.sup.® alumina was wetted with sufficient water toproduce an extrudable paste that was extruded through a die containingcloverleaf-shaped openings therein having a maximum dimension of about1/16 inch. The extruded product was cut into particles of about 1/8 to1/2 inch lengths, dried, and calcined. The calcined particles (i.e., theextrudates) were thus of a shape similar to that shown in FIGS. 8 and 8Aof U.S. Pat. No. 4,028,227 issued to Gustafson. The extrudates (200 gm)were then impregnated with nickel and tungsten components by contactwith 220 ml of an aqueous solution prepared by dissolving 67 gm nickelnitrate (Ni(NO₃)₂ ·6H₂ O) and 108 gm ammonium metatungstate (91% WO₃ byweight) into 330 ml of water. The resulting impregnated composite wasdried and then calcined at 900° F. The final catalyst consisted of about2.94 wt. % nickel components, calculated as NiO, about 21.5 wt. %tungsten components, calculated as WO₃, and the balance silicalite andgamma alumina in a 30:70 weight ratio, with the silicalite containingabout 0.6 wt. % alumina.

                                      TABLE II                                    __________________________________________________________________________    FEEDSTOCK AND PRODUCT COMPOSITION AND PROPERTIES                                         Feedstock                                                          __________________________________________________________________________    Product Sample                                                                           --    A-2 A-4  A-11 A-18 A-25 A-39                                                                              A-41                             Designation                                                                   Days into Run                                                                            --    2   4    11   18   25   39  41                               Gravity, °API                                                                     35.0  37.3                                                                              36.0 37.3 37.2 37.5 36.7                                                                              37.6                             Pour Point, ° F.                                                                  +80   +5  +15  +20  +20  +10  -5  +5                               Viscosity at 100° F.                                                              6.50  4.526                                                                             5.320                                                                              4.818                                                                              4.886                                                                              4.421                                                                              5.155                                                                             4.225                            cSt                                                                           Viscosity at 140° F.                                                              3.84  2.863                                                                             3.273                                                                              3.020                                                                              3.046                                                                              2.857                                                                              3.185                                                                             2.709                            cSt                                                                           Nitrogen, wppm                                                                           900   179 184  197  197  165  184 179                              Sulfur, wppm                                                                             41    16  15   7    15   10   15  16                               Simulated Distillation                                                        Vol. % Boiling Under                                                          80° F.                                                                            0     1.03                                                                              0.44 0.84 1.07 1.14 0.37                                                                              0.47                             300° F.                                                                           4.06  10.25                                                                             7.69 9.03 9.08 11.16                                                                              9.04                                                                              10.32                            520 ° F.                                                                          32.91 41.94                                                                             37.82                                                                              40.67                                                                              39.31                                                                              43.01                                                                              38.87                                                                             44.35                            670° F.                                                                           56.09 65.74                                                                             62.82                                                                              64.34                                                                              63.18                                                                              65.71                                                                              62.53                                                                             67.01                            750° F.                                                                           68.05 76.57                                                                             74.17                                                                              75.13                                                                              74.39                                                                              76.21                                                                              73.92                                                                             77.08                            __________________________________________________________________________

Results of the foregoing experiment are shown in Table II wherein datarelative to the composition and properties of the product shale oil atvarious times during the run are tabulated. As shown, the catalyst ofthe invention is highly active for reducing the organosulfur content,the organonitrogen content, and the pour point of the feedstock.Additionally, the catalyst of the invention proves highly active forselective hydrocracking of waxy components, with less than about 30%,usually less than about 25%, of the 750° F.+ fraction being converted tocomponents boiling below 750° F. and less than about 20% of the 670° F.+fraction being converted to products boiling below 670° F., even whenthe resultant pour point is in the 0° to +30° F. range. Of course, itcan be expected that if pour points lower than those shown in Table IIare desired, then more severe conditions would be required, which severeconditions would result in increased cracking of the heavy fraction. Butfor purposes of producing a " pipelineable" shale oil (i.e., a shale oilhaving a pour point of +30° F. or less), the data in Table II clearlyindicate that pour points as low as -5° F. are obtainable with far lessthan half the heavy fraction being converted to lower boilingcomponents.

Also evident from the data in Table II is that the catalyst of theinvention is not only highly active under the conditions utilized in theexperiment but also highly stable, evincing (after the catalyst achievedequilibrium on about the third day) no deactivation for the intendedhydrodewaxing and hydrotreating reactions through the forty-first day.(It should also be noted that the catalyst had, prior to the experiment,been utilized for fifty-seven days under dewaxing conditions similar tothose described above, the only significant difference being thatethylenediamine was fed to simulate the presence of ammonia. Despitesuch previous use, the catalyst of the invention remained highly activeunder the conditions of the experiment for the time period reported inTable II, as well as for the next eighty-eight days. All totaled, thecatalyst proved active for 186 days of operation and at the end of theexperiment showed virtually no signs of deactivation.)

When the product compositions obtained from the experiment described inExample I were further evaluated, it was unexpectedly found that threefractions thereof, the diesel fraction having a true boiling point range(as opposed to an ASTM distillation range) of 300° to 670° F., the Jet Aturbine fuel fraction of 300° to 520° F., and the JP-4 turbine fuelfraction consisting of components boiling at or below 470° F., all metappropriate freeze point and/or pour point requirements whereas thehydrotreated feedstock did not. The diesel fraction obtained in theprocess of the invention had a pour point no greater than +5° F., theJet A fraction had a freeze point no greater than -40° F., and the JP-4fraction had a freeze point no greater than -72° F. In view of thesefindings, it is a specific embodiment of the invention to subject anessentially full boiling range shale oil of high pour point, andparticularly a shale oil derived from an oil shale of the Colorado Riverformation, to catalytic hydro-treating followed by catalytichydrodewaxing, the latter using a catalyst of the invention, underconditions such that a product is obtained containing one or more of adiesel fraction, a Jet A fraction, and a JP4 fraction meeting the pourpoint and/or freeze point specifications set forth above. Thesefractions may then be recovered by conventional distillation methods.

EXAMPLE II

Three catalysts were tested to compare their activities forsimultaneously hydrodewaxing and hydrotreating a deasheddearsenatedshale oil feedstock having the properties and characteristics as shownin the following Table III:

                  TABLE III                                                       ______________________________________                                        Properties and Characteristics of Feedstock                                   ______________________________________                                        Gravity, °API @60° F.                                                            21.3    Distillation, D-1160, °F.                     Pour Point, °F.                                                                         55      IBP/5     210/377                                    Viscosity @100° F., SUS                                                                 154.2   10/20     446/535                                    Viscosity @140° F., SUS                                                                 71.4    30/40     614/692                                    Sulfur, wt. %    0.835   50/60     760/817                                    Nitrogen, Total, wt. %                                                                         1.80    70/80     869/929                                    Hydrogen, wt. %  11.61   90/95     1000/1047                                  Total Olefins, wt. %                                                                           18.8    Max/Rec.  1081/97.6                                  Aniline Point, °C.                                                                      40.3                                                         Arsenic, wppm    0.7                                                          Oxygen, wppm     119                                                          ______________________________________                                    

(The foregoing feedstock is the one from which the feedstock of ExampleI was derived by hydrotreating in the presence of Catalyst B hereinafterdescribed.)

The three catalysts utilized to treat the feedstock of Table III aredescribed as follows:

Catalyst A

This catalyst was prepared in a manner similar to that of Example I andwas of essentially the same composition and particulate shape.

Catalyst B

This catalyst was a commercially available hydrotreating catalystcontaining about 18 wt. % molybdenum components, calculated as MoO₃, 2.9wt. % nickel components, calculated as NiO, and 3.2 wt. % phosphoruscomponents, calculated as P, the balance being gamma alumina. Thecatalyst was in the form of particles having a three-leaf clovercross-sectional shape.

Catalyst C

This catalyst, being in the form of particles having three-leaf clovercross-sectional shapes similar to Catalysts A and B, consistedessentially of 3.90 weight percent of nickel components, calculated asNiO, and 23.2 weight percent tungsten components, calculated as WO₃, ona support of silica uniformly dispersed in a matrix of alumina. Thesupport was composed of 25% by weight silica and 75% by weight aluminaand had a surface area of 224 m² /gm.

The foregoing catalysts were each utilized under the followingconditions: 2000 psig, H₂ feed rate of 10,000 scf/bbl of feed, and 1.0LHSV. Temperatures were varied between about 749° and 820° F., and theresults of so varying the temperature for each of Catalysts A, B, and Cwith respect to the pour point, sulfur content, and nitrogen content ofthe product is shown in the following Table IV:

                  TABLE IV                                                        ______________________________________                                        Product Sulfur, Nitrogen, and Pour Point                                      Operating                                                                     Tem-                                                                          perature,                                                                             Pour Point °F.                                                                     Nitrogen, wppm                                                                             Sulfur, wppm                                 °F.                                                                            A      B     C    A    B    C    A    B   C                           ______________________________________                                        749     --     --    80   --   --   1230 --   --  107                         760      65    75    --   --   165  --   773  46  --                          780      70    75    80   465  55   84   50   46  30                          800     -10    75    --   118  9    --   23   23  --                          810     --     --    55   --   --   5    --   --  18                          820     -50    70    --   --   4    --   22   22  --                          ______________________________________                                    

The foregoing data clearly show the high activity of the catalyst of theinvention for simultaneously reducing the pour point, sulfur content,and nitrogen content of the shale oil feedstock at temperatures above780° F. Catalysts B and C exhibit little hydrodewaxing activity,although both showed high denitrogenation and desulfurization activity.The lack of hydrodewaxing activity in Catalysts B and C is attributable,at least in part, to the absence of a cracking component. The comparisonof this Example is provided mainly to illustrate that the catalyst ofthe invention has hydrotreating activity approaching that of typicalhydrotreating catalysts.

Although the data in Example II demonstrate the effectiveness of thecatalyst of the invention for treating a full boiling range shale oilfeedstock containing large proportions of organonitrogen andorganosulfur components, it is preferred in the invention that the shaleoil feedstock be catalytically hydrotreated, as for example, by contactwith a conventional catalyst comprising Group VIB and Group VIII metalcomponents under conditions of elevated temperature and pressure and inthe presence of added hydrogen, prior to being contacted with thecatalyst of the invention. Any suitable, conventional hydrotreatingcatalyst may be utilized for this purpose, especially those composed ofnickel, molybdenum, and phosphorus components supported on alumina. Ingeneral, hydrotreating catalysts suitable for pretreating the shale oilfeedstock comprise Group VIB metal components, particularly those ofmolybdenum and tungsten, and Group VIII metal components, particularlythose of nickel and cobalt, on a porous refractory oxide, such as thoselisted hereinbefore with respect to the catalyst of the invention, withalumina being preferred. The catalyst utilized for hydrotreating in thismanner may comprise Group VIB and Group VIII metal components(particularly the sulfides) in proportions as set forth hereinbeforewith respect to the catalyst of the invention.

It is, as stated before, a highly preferred embodiment of the inventionto treat a deashed-dearsenated, full boiling range shale oil feedstockby the method of the invention wherein the shale oil is firstcatalytically hydrotreated and then subjected to simultaneoushydrotreating and hydrodewaxing in the presence of the catalyst of theinvention. One of the peculiarities of many waxy shale oil feedstocks isthat hydrotreating substantially raises the pour point thereof. Forexample, in the data presented in Example II, it will be noticed thatthe shale oil feedstock had a pour point of +55° F. but that, for eachof the catalysts described in Example II, the pour point was raised whenthe conditions were such that the catalyst could only promotehydrotreating reactions. This curious result is believed due to the factthat hydrotreating saturates olefins, thereby producing paraffins,which, for shale oils produced from oil shales of the Colorado Riverformation, tend to be highly waxy. In any event, it is a specificembodiment of the invention to treat waxy shale oil feedstockscontaining organonitrogen compounds and/or organosulfur compounds byfirst catalytically hydrotreating the feedstock so that a substantialproportion of the organonitrogen and/or organosulfur compounds areremoved but the pour point is substantially increased and thencontacting the hydrotreated product with the hydrodewaxing catalystunder appropriate conditions such that yet further removal oforganonitrogen compounds and/or organosulfur compounds is accomplishedand, concomitant therewith, the pour point of the hydrotreated shale oilis reduced to a value substantially below that of the originalfeedstock. In accordance with this embodiment of the invention, adeashed-dearsenated, full boiling range shale oil feedstock having apour point above about 50° F. and containing more than about 0.20 wt. %organosulfur components and more than about 1.50 wt. % organonitrogencomponents, calculated as sulfur and nitrogen, respectively, arecatalytically hydrotreated in the presence of a typical, sulfidedhydrotreating catalyst containing a Group VIB metal (e.g., Mo, W) and aGroup VIII metal (e.g., Ni, Co) on a porous refractory oxide, preferablyalumina, under conditions such that the pour point rises above about 70°F. while the organonitrogen content drops to between about 200 and 3500wppm, usually between 300 and 2000 wppm, and often between 300 and 1000wppm, and the organosulfur content drops to between about 30 and 2000wppm. The entire effluent obtained in the hydrotreating stage, includingthe unreacted hydrogen and the produced ammonia and hydrogen sulfide, isthen passed to a reactor containing the catalyst of the invention inparticulate form. Preferably, the outlet temperature of the effluent ofthe hydrotreating stage is the same as, or within about 25° F. of, theinlet temperature of the feed to the second stage containing thehydrotreatingdewaxing catalyst. Conditions in the second stage are suchas to produce a product shale oil having a pour point below about 30°F., preferably below 25° F., an organosulfur content below about 25wppm, preferably below 20 wppm, and an organonitrogen content belowabout 400 wppm, preferably below 100 wppm. Conditions from which suchresults may be produced from typical deashed-dearsenated shale oil feedswith the hydrotreating and hydrodewaxing-hydrotreating catalystsdescribed in Example I hereinbefore are as follows:

                  TABLE V                                                         ______________________________________                                                                  Simultaneous Hydro-                                                           treating-                                           Condition     Hydrotreating                                                                             Hydrodewaxing                                       ______________________________________                                        Space Velocity, LHSV                                                          Suitable      0.1-2.0     0.1-10                                              Preferred     0.3-0.7     0.5 -2.0                                            Temperature, °F.                                                       Suitable      >650        >650                                                Preferred     700-775     700-780                                             Highly Preferred                                                                            725-745     720-750                                             Pressure, psig                                                                Suitable      >750        >750                                                Preferred     1500-2500   1500-3000                                           Highly Preferred                                                                            2000-2500   2000-2500                                           H.sub.2 Added Plus H.sub.2 in                                                 Recycle Gas, scf/bbl                                                          Suitable      >500        >500                                                Preferred      >2000      1500-15,000                                         Highly Preferred                                                                            4000-7000   6000-10,000                                         ______________________________________                                    

The following Example illustrates a method for treatingdeashed-dearsenated shale oil by hydrotreating followed by simultaneoushydrotreating-hydrodewaxing.

EXAMPLE III

In an experiment designed to determine the effectiveness of subjecting adeashed-dearsenated shale oil feedstock to catalytic hydrotreatingfollowed by simultaneous hydrotreating-hydrodewaxing with the catalystof the invention, an experiment was conducted over about a nine-monthperiod. In the experiment, deashed-dearsenated, waxy shale oilfeedstocks typically having the properties and characteristics shown inthe following Table VI:

                  TABLE VI                                                        ______________________________________                                        Gravity, °API                                                                        25.1     Modified Vacuum Engler                                                        Distillation, Volume Percent                           Hydrogen, wt. %                                                                             11.95    Cut Versus Temperature, °F.                     Nitrogen, kjel, wt. %                                                                       1.75     IBP/5      233/346                                     Sulfur, X-ray, wt. %                                                                        0.409    10/20      400/532                                     Oxygen, wt. % 0.842    30/40      615/693                                     Analine Point, °F.                                                                   121      50/60      758/814                                     Pour Point, °F.                                                                      +76      70/80      871/922                                     Viscosity @210°F., SSU                                                               38.2     90/95       981/1025                                   Carbon Residue, D189,                                                                       0.5      EP at 98.7%                                                                              1072                                        wt. %                                                                         ______________________________________                                    

were first subjected to catalytic hydrotreating in an appropriatereactor vessel containing a catalyst of composition and propertiessimilar to that of Catalyst B in Example II, following which the entireeffluent recovered from hydrotreating was passed downwardly through asecond reactor vessel containing the hydrotreating-hydrodewaxingcatalyst of the invention. This catalyst was in the form of 1/16 inchdiameter cylindrical extrudates of about 1/4 to 3/4 inch particlelength. The catalyst was composed of 2.9 wt.% nickel components,calculated as NiO, and 21.5 wt.% tungsten components, calculated as WO₃,on a support consisting essentially of 70 wt.% alumina and 30 wt.%silicalite containing 0.74 wt.% alumina. The operating conditions wereas shown in the following Table VII:

                  TABLE VII                                                       ______________________________________                                                               Hydrotreating-                                                      Hydrotreating                                                                           Dewaxing                                               ______________________________________                                        Pressure, psig 2225        2225                                               Space Velocity, LHSV                                                                         0.59        1.0                                                Reactor Temperatures, °F.                                                             715-735     740-780                                            Catalyst Charge, gm                                                                          431         300*                                               Gas Rate, scf/bbl                                                                            5500        8000                                               H.sub.2 Concentration in Gas,                                                                91          91                                                 mole %                                                                        ______________________________________                                         *Note: During a portion of the run, the catalyst charge also contained, a     the bottom of the bed, 30 grams of Catalyst B.                           

Temperatures were varied in the hydrotreating andhydrotreating-hydrodewaxing reactors during the experiment. It was foundthat varying the temperatures within the ranges shown in Table VII forhydrotreating resulted in a dramatic decrease in the organonitrogencontent in the effluent therefrom, usually from the 1.75 wt.% value forthe feedstock to less than 1000 wppm, and with temperatures above 730°F., to 500 wppm or less. Temperature was also varied in thehydrotreating- hydrodewaxing reactor, largely for the purpose oflowering the pour point of the incoming liquid phase but also for thepurpose of further lowering the organonitrogen and organosulfur contentsof the effluent from the hydrotreating reactor. The organonitrogencontent of the product recovered from the hydrotreating-hydrodewaxingreactor was consistently below 200 wppm, and consistently below 100 wppmwhen temperatures above 730° F. were utilized in the first-stagehydrotreating reactor. Also, the organosulfur content was consistentlymaintained below 25 wppm, often below 20 wppm, while the pour pointdecreased considerably with increases in the operating temperature ofthe hydrotreating-hydrodewaxing reactor. Some data derived fromoperating at three different temperatures in thehydrotreating-hydrodewaxing reactor are presented in the following TableVIII wherein "TBP" refers to the true boiling point range of thefraction specified:

                  TABLE VIII                                                      ______________________________________                                        Average Bed Reactor                                                                         745       760       780                                         Temperature, °F.                                                       Pour Point, °F.                                                                      +25       0         -25                                         Maximum JP-4*:                                                                TBP Cuts, °F.                                                                        C.sub.5 -480                                                                            C.sub.5 -480                                                                            C.sub.5 -510                                Yield, vol. % 34        42        52                                          Heavy Diesel:                                                                 TBP Cuts, °F.                                                                        480-620   480-640   510-620                                     Yield, vol. % 25        29        20                                          Fuel Oil: - TBP Cuts, °F.                                                            620+      640+      620+                                        Yield, vol. % 49        33        28                                          Light Naphtha:                                                                TBP Cuts, °F.                                                                        C.sub.5 -280                                                                            C.sub.5 -270                                                                            C.sub.5 -270                                Yield, vol. % 8         8         10 Maximum                                  Diesel:                                                                       TBP Cuts, °F.                                                                        280-680   270-720   270-760                                     Yield, vol. % 61        73        78                                          Oil:                                                                          TBP Cuts, °F.                                                                        680+      720+      780+                                        Yield, vol. % 35        23        12                                          ______________________________________                                         *Note: JP4 fractions obtained when the hydrotreatinghydrodewaxing reactor     contained 30 gm. of Catalyst B consistently met the JFTOT stability test,     ASTM D3241-77 entitled "Test for Thermal Oxidation Stability of Aviation      Turbine Fuels.                                                           

In the foregoing example, the entire effluent from the hydrotreater waspassed to the reactor containing the hydrotreating-hydrodewaxingcatalyst of the invention. This is the preferred embodiment of theinvention. However, in other embodiments of the invention wherein waxyorganonitrogen containing feedstocks are treated by the above-describedtwo-step procedure, it may be desirable to remove ammonia from theeffluent of the hydrotreating stage so that the feed to the simultaneoushydrodewaxing-hydrotreating stage contains essentially no ammonia. Thismay be accomplished by any convenient means, such as absorption in acaustic solution. This procedure has the advantage of removing a knownhydro cracking deactivating component, i.e., ammonia, from the materialin contact with the catalyst of the second stage. In this embodiment ofthe invention, one obtains much reduced pour points under otherwisesimilar operating conditions. But such a method in many instances iseither unnecessary, the pour point being reduced sufficiently even inthe presence of ammonia, or too costly, requiring additional capitalexpense for a scrubber or the like.

The following Example provides a comparison between catalysts of theinvention and a catalyst of similar composition but containing ZSM-5 inplace of silicalite.

EXAMPLE IV

A deashed-dearsenated-hydrotreated shale oil, designated F-3420, had theproperties and characteristics shown in the following Table IX:

                  TABLE IX                                                        ______________________________________                                        Gravity, °API                                                                        35.0     ASTM Distillation, D-1160                              Pour Point    +80      Initial BP 223° F.                              Kinematic Viscosity    10%        394° F.                              at 100° F., cSt                                                                      6.50     50%        660° F.                              at 100° F., SUS                                                                      47.2     90%        914° F.                              Nitrogen, wppm                                                                              900      EP         1027° F.                             Sulfur, wppm  41                                                              ______________________________________                                    

This feedstock was obtained by electrostatically deashing a raw, fullrange shale oil derived from retorting Colorado oil shale, dearsenatingthe resulting deashed shale oil by a method described in U.S. Pat. No.4,046,674 such that the resultant product was not only virtually free ofarsenic but contained 1.8 wt.% nitrogen and 0.835 wt.% sulfur and had apour point of 55° F. This deashed-dearsenated product was thenhydrotreated under conditions of elevated temperature and pressure inthe presence of added hydrogen and a sulfided catalyst comprising about18 wt.% molybdenum components, calculated as Mo0₃, about 3 wt.% nickelcomponents, calculated as NiO, and about 3 wt.% phosphorus components,calculated as P, on a gamma alumina support having a three-leaf clovercross-sectional shape.

To simulate the entire effluent recovered from hydrotreating, tertiarybutylamine and thiophene were added to the F-3420 feedstock. Thetertiary butylamine and thiophene were added at rates sufficient tosimulate the amount of ammonia and H₂ S, respectively, that would beproduced by hydrotreating a feedstock containing 1.8 wt.% organonitrogencomponents, calculated as nitrogen, and 0.84 wt.% organosulfurcomponents, calculated as sulfur.

The foregoing feedstock containing added thiophene and tertiarybutylamine was passed in separate runs through a reactor containing fivedifferent samples of catalyst particles under the following conditions:2000 psig, 1.0 LHSV, 8000 scf/bbl once through H₂ -to-oil ratio, 266lbs/hr-ft² mass velocity, and temperature varied to provide a producthaving a +30° F. pour point. One catalyst used in the experiment,Catalyst A, consisted essentially of 2.6 wt.% NiO and 20.3 wt.% WO₃ onclover-leaf-shaped supports consisting essentially of 30 wt.% ZSM-5 inthe hydrogen form and the balance being alumina, with the ZSM-5containing about 3 wt.% alumina. A second catalyst, Catalyst B,consisted essentially of 3.6 wt.% NiO and 2.55 wt.% WO₃ on 1/16 inchdiameter cylindrical supports consisting essentially of 30 wt.%silicalite and the balance alumina, the silicalite containing about 0.74wt.% alumina. The third catalyst, Catalyst C, was similar to Catalyst Bbut contained 2.9 wt.% NiO and 21.5 wt.% WO₃ and had clover-leaf-shapedsupports comprising 30 wt.% silicalite containing 0.6 wt.% alumina. Thefourth catalyst, Catalyst D, was similar to Catalyst B but comprised 3.3wt.% NiO and 22.3 wt.% WO₃ on cylindrical supports comprising 30 wt.%silicalite containing about 0.44 wt.% alumina. And the fifth catalyst,Catalyst E, was also similar to Catalyst B but contained 5 wt.% NiO and22 wt.% WO₃ on a clover-leaf-shaped support comprising 30 wt.%silicalite containing 44 wppm (0.0044 wt.%) alumina. The reactortemperatures required to produce a +30° F. pour point product aretabulated in the following Table X:

                  TABLE X                                                         ______________________________________                                                                 Average Bed Reactor                                                           Temperature to Yield                                                          +30° F. Pour Point                            Catalyst                                                                             Dewaxing Component                                                                              Product                                              ______________________________________                                        A      ZSM-5; 3.0 wt. % Al.sub.2 O.sub.3                                                               747° F.                                       B      Silicalite; 0.74 wt. % Al.sub.2 O.sub.3                                                         739° F.                                       C      Silicalite; 0.6 wt. % Al.sub.2 O.sub.3                                                          743° F.                                       D      Silicalite; 0.44 wt. % Al.sub.2 O.sub.3                                                         745° F.                                       E      Silicalite; 0.0044 wt. % Al.sub.2 O.sub.3                                                       797° F.                                       ______________________________________                                    

As shown by the foregoing, the dewaxing activity ofsilicalite-containing catalysts wherein the silicalite contains aluminain a proportion between about 0.15 and 0.75 wt.% is greater than ZSM-5for reducing the pour point of shale oil feedstocks. This result isconsidered very surprising. It has been reported that the activity ofthe ZSM-5 type zeolites varies directly with the proportion of alumina.For example, in "Chemical and Physical Properties of the ZSM-5Substitutional Series" by D. H. Olson et al. published in the Journal ofCatalysis, Vol. 61, pp 390-396 (1980), it is taught that hexane crackingactivity of ZSM-5 drops off linearly as the alumina content decreasesand falls to zero when the alumina content becomes zero. The reasonoffered by Olson et al. for this linear dependence of cracking activityupon alumina content is that activity is dependent upon the number ofacid sites in ZSM-5, which in turn is dependent upon the aluminacontent. Based in part upon this hexane cracking data, Olson et al.conclude that silicalite " appears to be a member of the ZSM-5substitutional series." But as shown by the data in the above Table X,silicalite has properties not predictable from those of ZSM-5. Morespecifically, Catalysts B, C, and D all contained silicalites of farlower alumina concentration than ZSM-5 but demonstrated greater activityfor the cracking reactions involved in hydrodewaxing shale oils. Eventhe activity of Catalyst E, which contained silicalite having only 44wppm alumina, was surprising. According to the linear relationshipproposed by Olson et al., this silicalite should have virtually nocracking activity, yet it demonstrated sufficient activity to yield a+30° F. pour point product at an operating temperature below 800° F.

In the following example, it is shown how the catalyst of the inventionmay be utilized to produce lubricating oils from waxy raffinates.

EXAMPLE V

A silicalite-containing catalyst of similar composition to thatdescribed in Example III was used to selectively hydrocrack a waxyraffinate to produce a low pour point lube stock. The raffinate had theproperties and characteristics shown in the following Table XI:

                  TABLE XI                                                        ______________________________________                                        Gravity, °API                                                                       29.1    ASTM Distillation, D-1160, °F.                    Pour Point, °F.                                                                     102     IBP        660                                           Wax, wt. %   18.0     5%        726                                           Sulfur, wt. %                                                                              0.053   10%        748                                           Nitrogen, wt. %                                                                            0.014   30%        793                                           Kinematic Viscosity  50%        841                                           at 140° F., cSt.                                                                    25.47   70%        929                                           at 210° F., sCt.                                                                    8.395   90%        1065                                          ______________________________________                                    

Test conditions were as follows: 600 psig, 2500 scf/bbl of once-throughhydrogen, and 1.0 liquid hourly space velocity. Operation at 729° F.yielded a product hydrocarbon containing 58.5% by volume of a 700° F.+fraction having a +20° F. pour point, a kinematic viscosity at 100° F.of 85.91 cSt, a kinematic viscosity at 210° F. of 9.92 cSt, and aviscosity index of 93.6. Also, the product hydrocarbon contained only 60wppm of organonitrogen components and 10 wppm of organo-sulfurcomponents.

In the foregoing experiment, it was unexpectedly discovered that, whenammonia was blended into the waxy raffinate being treated for dewaxing(in the form of tertiary butylamine), the gravity of the productremained essentially equal to that of the feed while the pour point waslowered to about +20° F. These results suggest that ammonia retards orprevents the degradation of the high boiling components in waxyraffinates to lower boiling constituents during the dewaxing treatmentand that ammonia tends to increase the selectivity of the catalyst ofthe invention for cracking normal paraffins. It is also believed thatthe addition of ammonia will aid in increasing the viscosity index ofthe product lubricating oil.

Although the invention has been described in conjunction with examplesthereof, including comparative examples, many modifications, variations,and alternatives of the invention as described will be apparent to thoseskilled in the art. For example, in many processes for treatinghydrocarbons liquids, the liquid is hydrotreated catalytically to removesulfur and/or nitrogen components, following which the entire effluent,or a portion thereof, is hydrocracked catalytically using a catalystcontaining Group VIB and VIII metals on a support containing a zeolite.Often, because hydrocrackate product is recycled to the stream enteringthe hydrocracker, the waxy paraffin content of the hydrocarbon streamentering the hydrocracker becomes excessive, and it can be seen that thecatalyst of the invention may be placed in the hydrocracker, as forexample, as a layer of catalyst above the hydrocracking catalyst, sothat the hydrocarbon stream passing downwardly through the hydrodewaxingcatalyst of the invention an then through the hydrocracking catalyst isfirstly dewaxed to lower the waxy paraffin content and then hydrocrackedto yield desired products. This embodiment of the invention isespecially contemplated for producing high end point jet fuels.

Accordingly, it is intended to embrace within the claimed subject matterall variations, modifications, and alternatives to the invention as fallwithin the spirit and scope of the appended claims.

We claim:
 1. A catalyst composition comprising a Group VIB metalcomponent and a Group VIII metal component on a support comprising anadmixture of a porous refractory oxide and a silica polymorph consistingessentially of crystalline silica.
 2. A catalyst composition useful forpromoting the dewaxing of hydrocarbons by reaction with hydrogen, whichcatalyst comprises a Group VIB metal component and a Group VIII metalcomponent on a support consisting essentially of a porous refractoryoxide and a silica polymorph consisting essentially of crystallinesilica.
 3. A catalyst composition useful for promoting the simultaneousdewaxing and denitrogenation of hydrocarbons by reaction with hydrogen,which catalyst comprises a Group VIB metal component and a Group VIIImetal component on a support comprising an intimate admixture of aporous refractory oxide and a silica polymorph consisting essentially ofa crystalline silica molecular sieve.
 4. A catalyst composition asdefined in claim 1 or 3 wherein said silica polymorph contains GroupIIIA metals in a proportion no greater than 0.75 weight percent,calculated as the trioxides thereof.
 5. A catalyst composition asdefined in claim 2 or 3 wherein said silica polymorph comprises acrystalline molecular sieve having channels with openings defined by tenmembered rings of oxygen atoms.
 6. A catalyst composition as defined inclaim 5 wherein the Group IIIA metal content of said silica polymorph isless than 0.75 weight percent, calculated as the trioxides.
 7. Acatalyst composition as defined in claim 1 or 2 wherein said silicapolymorph contains channels whose maximum cross-sectional dimension isbetween about 5 and about 6 angstroms.
 8. A catalyst composition asdefined in claim 1, 2, or 3 wherein said silica polymorph is a form ofsilicalite.
 9. A catalyst composition as defined in claim 2 wherein saidsilica polymorph is a silicalite having a specific gravity at 25° C. of1.70±0.5 g./cc. and a mean refractive index of 1.39±0.01 when calcinedin air for one hour at 600° C.
 10. A catalyst composition as defined inclaim 1, 2, or 3 wherein said silica polymorph has a specific gravity at25° C. between about 1.65 and 1.80 g./cc.
 11. A catalyst composition asdefined in claim 1 or 3 wherein said silica polymorph has an X-raydiffraction pattern similar to ZSM-5.
 12. A catalyst composition asdefined in claim 5 wherein said silica polymorph has an X-raydiffraction pattern whose six strongest lines are as set forth in thefollowing table, wherein S refers to strong lines and VS to very stronglines:

    ______________________________________                                        d-A          Relative Intensity                                               ______________________________________                                        11.1 ± 0.2                                                                              VS                                                               10.0 ± 0.2                                                                              VS                                                               3.85 ± 0.07                                                                             VS                                                               3.82 ± 0.07                                                                             S                                                                3.76 ± 0.05                                                                             S                                                                3.72 ± 0.05                                                                             S                                                                ______________________________________                                    


13. A catalyst composition as defined in claim 1 or 2 wherein saidsilica polymorph has an X-ray diffraction pattern whose six strongestlines are as set forth in the following table, wherein S refers tostrong lines and VS to very strong lines:

    ______________________________________                                        d-A          Relative Intensity                                               ______________________________________                                        11.1 ± 0.2                                                                              VS                                                               10.0 ± 0.2                                                                              VS                                                               3.85 ± 0.07                                                                             VS                                                               3.82 ± 0.07                                                                             S                                                                3.76 ± 0.05                                                                             S                                                                3.72 ± 0.05                                                                             S                                                                ______________________________________                                    


14. A catalyst composition as defined in claim 7 wherein said silicapolymorph has an X-ray diffraction pattern similar to ZSM-5.
 15. Acatalyst composition as defined in claim 5 wherein said silica polymorphcontains less than 0.75 weight percent total metals, calculated asmetals.
 16. A catalyst composition as defined in claim 13 wherein saidsilica polymorph contains less than 0.75 weight percent total metals,calculated as metals.
 17. A catalyst composition as defined in claim 11wherein said silica polymorph contains less than 0.75 weight percenttotal metals, calculated as metals.
 18. A catalyst composition asdefined in claim 17 wherein said Group VIB metal component is selectedfrom the group consisting of tungsten, molybdenum, the sulfides thereof,the oxides thereof, and mixtures thereof, and said Group VIII metalcomponent is selected from the group consisting of nickel, cobalt, thesulfides thereof, the oxides thereof, and mixtures thereof.
 19. Acatalyst composition as defined in claim 6 wherein said Group VIB metalcomponent is selected from the group consisting of tungsten, molybdenum,the sulfides thereof, the oxides thereof, and mixtures thereof, and saidGroup VIII metal component is selected from the group consisting ofnickel, cobalt, the sulfides thereof, the oxides thereof, and mixturesthereof.
 20. A catalyst composition as defined in claim 8 wherein saidGroup VIB metal component is selected from the group consisting oftungsten, molybdenum, the sulfides thereof, the oxides thereof, andmixtures thereof, and said Group VIII metal component is selected fromthe group consisting of nickel, cobalt, the sulfides thereof, the oxidesthereof, and mixtures thereof.
 21. A catalyst composition comprising aGroup VIB metal component and a Group VIII metal component on a supportcomprising a porous refractory oxide in intimate admixture with anessentially Group IIIA metal-free crystalline silica molecular sievehaving channels with apertures defined by ten membered rings of oxygenatoms.
 22. A catalyst composition comprising a Group VIB metal componentand a Group VIII metal component on a support comprising a porousrefractory oxide in intimate admixture with an essentially Group IIIAmetal-free crystalline silica molecular sieve said molecular sievecomprising between about 2 and 90 percent by weight of said support. 23.A catalyst composition as defined in claim 21 or 22 wherein saidmolecular sieve has an X-ray diffraction pattern similar to ZSM-5.
 24. Acatalyst composition as defined in claim 22 wherein said molecular sievecontains no more than 0.05 weight percent of organic materials,calculated as carbon.
 25. A catalyst composition as defined in claim 21wherein the specific gravity of said molecular sieve is between about1.65 and 1.80 cc./gm at 25° C.
 26. A catalyst composition as defined inclaim 21 or 22 wherein said molecular sieve is a form of silicalite. 27.A catalyst composition as defined in claim 26 wherein said silicalitehas a mean refractive index of 1.39±0.01.
 28. A catalyst composition asdefined in claim 26 wherein said silicalite is essentially organic-free.29. A hydroprocessing catalyst composition consisting essentially of aGroup VIB metal component and a Group VIII metal component on a supportconsisting essentially of an intimate admixture of a porous refractoryoxide and a silica polymorph consisting essentially of crystallinesilica having a Group IIIA metal content less than 0.75 percent byweight, calculated as the trioxides, and an X-ray diffraction patternwhose six strongest lines are as set forth in the following table,wherein S refers to strong lines and VS to very strong lines:

    ______________________________________                                        d-A          Relative Intensity                                               ______________________________________                                        11.1 ± 0.2                                                                              VS                                                               10.0 ± 0.2                                                                              VS                                                               3.85 ± 0.07                                                                             VS                                                               3.82 ± 0.07                                                                             S                                                                3.76 ± 0.05                                                                             S                                                                3.72 ± 0.05                                                                             S                                                                ______________________________________                                    


30. A catalyst composition as defined in claim 29 wherein said Group VIBmetal component is a tungsten component and said Group VIII metalcomponent is a nickel component.
 31. A catalyst composition as definedin claim 30 wherein said porous refractory oxide is alumina.
 32. Acatalyst composition as defined in claim 1, 3, 9, 21, 24, or 29 whereinsaid Group VIB metal component is selected from the group consisting oftungsten, molybdenum, the sulfides thereof, the oxides thereof, andmixtures thereof, and said Group VIII metal component is selected fromthe group consisting of nickel, cobalt, the sulfides thereof, the oxidesthereof, and mixtures thereof.
 33. A catalyst composition comprisingbetween about 5 and 40 percent by weight of one or more Group VIB metalcomponents, calculated as the metal trioxides, and between about 0.5 and15 percent by weight of one or more Group VIII metal components,calculated as the metal monoxides, on a support consisting essentiallyof a porous refractory oxide and a silica polymorph consistingessentially of a crystalline silica having channels with apertures whosemaximum cross-sectional dimension is between about 5 and 6 angstroms,said crystalline silica being essentially free of Group IIIA metals. 34.A catalyst composition as defined in claim 33 wherein said silicapolymorph has an X-ray diffraction pattern similar to ZSM-5.
 35. Acatalyst composition as defined in claim 34 wherein said crystallinesilica is essentially free of organic components and said crystallinesilica contains less than 0.75 percent by weight of total metals.
 36. Acatalyst composition as defined in claim 33 or 35 wherein saidcrystalline silica is a form of silicalite.
 37. A catalyst compositionas defined in claim 36 wherein said Group VIB metal components areselected from the group consisting of molybdenum, tungsten, the oxidesthereof, the sulfides thereof, and mixtures thereof, and said Group VIIImetal components are selected from the group consisting of nickel,cobalt, the oxides thereof, the sulfides thereof, and mixtures thereof.38. A catalyst composition as defined in claim 24 or 34 wherein saidGroup VIB metal components are selected from the group consisting ofmolybdenum, tungsten, the oxides thereof, the sulfides thereof, andmixtures thereof, and said Group VIII metal components are selected fromthe group consisting of nickel, cobalt, the oxides thereof, the sulfidesthereof, and mixtures thereof.
 39. A catalyst composition useful forpromoting the simultaneous dewaxing and denitrogenation of hydrocarbonsby reaction with hydrogen, which catalyst comprises at least 1.0 weightpercent of a Group VIII metal component selected from the groupconsisting of cobalt, nickel, the oxides thereof, the sulfides thereof,and mixtures thereof, and at least 10 weight percent of a Group VIBmetal component selected from the group consisting of molybdenum,tungsten, the oxides thereof, the sulfides thereof, and mixturesthereof, and a support comprising a porous refractory oxide and betweenabout 15 and 45 weight percent of a silica polymorph consistingessentially of crystalline silica.
 40. A catalyst composition as definedin claim 39 wherein said crystalline silica contains less than 0.75weight percent of Group IIIA elements and said refractory oxidecomprises alumina.
 41. A catalyst composition as defined in claim 40wherein said silica polymorph has, when calcined in air at 600° C. forone hour, a mean refractive index of 1.39±0.01 and a specific gravity at25° C. between 1.65 and 1.80 grams per cubic centimeter.
 42. A catalystcomposition useful for hydrodewaxing consisting essentially of betweenabout 1 and about 5 percent by weight of one or more Group VIII metalcomponents selected from the group consisting of cobalt, nickel, theoxides thereof, the sulfides thereof, and mixtures thereof, calculatedas the metal monoxides, and between about 15 and 30 percent by weight ofone or more Group VIB metal components selected from the groupconsisting of molybdenum, tungsten, the oxides thereof, the sulfidesthereof, and mixtures thereof, calculated as the metal trioxides, on asupport consisting essentially of a porous refractory oxide in admixturewith between about 15 and 45 percent by weight of the support of asilicalite having an X-ray diffraction pattern similar to ZSM-5 and aspecific gravity at 25° C. between about 1.65 and 1.80 g./cc.
 43. Acatalyst composition as defined in claim 42 wherein said silicalite isessentially organic-free and contains metals in a proportion no greaterthan 0.75 percent by weight.
 44. A catalyst as defined in claim 43wherein said silicalite is present in a proportion between about 20 and40 percent by weight.
 45. A catalyst as defined in claim 42 or 44wherein said Group VIB metal component is selected from the groupconsisting of tungsten, tungsten oxides, and tungsten sulfides, and saidGroup VIII metal is selected from the group consisting of nickel, nickeloxides, and nickel sulfides.
 46. A catalyst composition useful forsimultaneous dewaxing, denitrogenation and desulfurization ofhydrocarbons by reaction with hydrogen consisting essentially of betweenabout 1 and about 5 percent by weight of nickel components, calculatedas NiO, and between about 15 and 30 percent by weight of tungstencomponents, calculated as WO₃, on a support consisting essentially of aporous refractory oxide in admixture with between about 20 and 40percent by weight of the support of an organic-free silicalite having aspecific gravity at 25° C. of 1.70±0.5 g./cc., a mean refractive indexof 1.39±0.01, and an X-ray diffraction pattern whose six strongest linesare as set forth in the following table, wherein S refers to stronglines and VS to very strong lines:

    ______________________________________                                        d-A          Relative Intensity                                               ______________________________________                                        11.1 ± 0.2                                                                              VS                                                               10.0 ± 0.2                                                                              VS                                                               3.85 ± 0.07                                                                             VS                                                               3.82 ± 0.07                                                                             S                                                                3.76 ± 0.05                                                                             S                                                                3.72 ± 0.05                                                                             S                                                                ______________________________________                                    


47. A catalyst composition as defined in claim 22, 33, 42, or 46 whereinsaid catalyst is in a sulfided form.
 48. A catalyst composition asdefined in claim 35 or 46 wherein said porous refractory oxide isselected from the group consisting of alumina, silica, beryllia,zirconia, titania, magnesia, thoria, silica-alumina, silica-titania,silica-zirconia, silica-zirconia-titania, zirconia-titania, a dispersionof silica-alumina in alumina, and mixtures thereof.
 49. A catalystcomposition as defined in claim 42 or 46 wherein said porous refractoryoxide is alumina.
 50. A catalyst composition as defined in claim 42 or46 wherein said porous refractory oxide is alumina having a surface areaabove about 100 m² /gm.
 51. A catalyst composition as defined in claim3, 21, or 22 wherein said porous refractory oxide comprises a memberselected from the group consisting of alumina, silica, beryllia,chromia, zirconia, titania, magnesia, thoria, silica-alumina,silica-titania, silica-zirconia, silica-zirconia-titania, andzirconia-titania and said crystalline molecular sieve has an X-raydiffraction pattern whose six strongest lines are as set forth in thefollowing table, wherein S refers to strong lines and VS to very stronglines:

    ______________________________________                                        d-A          Relative Intensity                                               ______________________________________                                        11.1 ± 0.2                                                                              VS                                                               10.0 ± 0.2                                                                              VS                                                               3.85 ± 0.07                                                                             VS                                                               3.82 ± 0.07                                                                             S                                                                3.76 ± 0.05                                                                             S                                                                3.72 ± 0.05                                                                             S                                                                ______________________________________                                    


52. A catalyst composition as defined in claim 1 or 39 wherein saidporous refractory oxide comprises a member selected from the groupconsisting of alumina, silica, beryllia, chromia, zirconia, titania,magnesia, thoria, silica-alumina, silica-titania, silica-zirconia,silica-zirconia-titania, and zirconia-titania and said silica polymorphhas an X-ray diffraction pattern whose six strongest lines are as setforth in the following table, wherein S refers to strong lines and VS tovery strong lines:

    ______________________________________                                        d-A          Relative Intensity                                               ______________________________________                                        11.1 ± 0.2                                                                              VS                                                               10.0 ± 0.2                                                                              VS                                                               3.85 ± 0.07                                                                             VS                                                               3.82 ± 0.07                                                                             S                                                                3.76 ± 0.05                                                                             S                                                                3.72 ± 0.05                                                                             S                                                                ______________________________________                                    


53. A catalyst composition as defined in claim 51 wherein saidcrystalline molecular sieve has a refractive index of 1.39+0.01.
 54. Acatalyst composition as defined in claim 52 wherein said silicapolymorph has a refractive index of 1.39±0.01.